This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. 1/14/2008 Recent progress in neuroimaging techniques has greatly advanced our understanding of attention and its neural network. A variety of theoretical frameworks have been proposed to illustrate the mental and neural mechanisms of attention and its role in cognitive and affective controls. However, several critical issues remain unsolved and call for further investigation. This application, combining advanced functional magnetic resonance imaging techniques and wellconceived theory-driven behavioral paradigms, will provide a foundation for generating refined hypotheses about the neural mechanism of attentional control. The unique approach of this proposal is to examine and account for different effects of attention and executive control under a unified framework of attentional control, dimensional overlap. According to this framework, compatibility of the stimulus and response sets can be categorized based on the dimensional overlap across the stimulus and response domains between the task-relevant and task-irrelevant dimensions. We hypothesize that the dimensional overlap across the stimulus and response domains between the task-relevant and taskirrelevant dimensions is the common driving force underlying various effects of attention in orienting and executive control. We propose the following two specific aims. Specific Aims: (1) To examine common and distinct neural substrates underlying conflict resolution of stimulusstimulus (S-S) and stimulus-response (S-R) incompatibility. We expect that the frontoparietal network will be commonly activated for both S-S and S-R incompatibility effects, whereas distinct brain areas in the inferior frontal cortex, inferior temporal cortex, and anterior cingulated cortex, will be responsible for the unique effects of S-S and S-R incompatibility. (2) To examine common and distinct neural substrates underlying attentional control of endogenous and exogenous orienting. We expect that the similar frontoparietal network will modulate people?s attention whereas endogenous and exogenous orienting of attention will rely on distinct brain regions reflecting top-down selection and bottom-up capture respectively. Specifically, top-down selection will recruit more dorsal regions such as the inferior parietal cortex and frontal eye field whereas bottom-up capture will selectively activate more ventral areas such as the temporal parietal junction and inferior frontal cortex. Significance. These studies will provide insight into the neural mechanism of attentional control and help researchers design better behavioral and therapeutic prevention and interventions to effectively target at-risk individuals, who suffer from attention-related deficits due to either neuropsychological insults or natural degradation of aging.